1. Field of the Invention
Example embodiments of the present invention relate to a composition for forming a photosensitive organic anti-reflective layer, and to a method of forming a pattern using the same. More particularly, example embodiments of the present invention relate to a composition for forming a photosensitive organic anti-reflective layer that is used for forming a photoresist pattern, and to a method of forming a pattern using the composition.
A claim of priority under 35 USC §119 is made to Korean Patent Application No. 2005-110044, filed on Nov. 17, 2005, the entire contents of which are herein incorporated by reference.
2. Description of the Related Art
During manufacture of a semiconductor device, a photoresist pattern is used as an etching mask in a photolithography process. To form the photoresist pattern, an anti-reflective layer is formed on a layer prior to deposition of a photoresist film.
The anti-reflective layer reduces the reflection of light from the layer when the photoresist film is patterned by an exposure process of the photolithography process. More particularly, the anti-reflective layer prevents or reduces a stationary wave effect caused by interference between incident light into the photoresist layer and reflected light from the photoresist layer during the exposure process.
Further, the anti-reflective layer prevents or reduces the reflection of light from a stepped portion of underlying patterns that have been formed by a previous fabrication process, and a diffused reflection of light from an edge of the underlying patterns. Therefore, the anti-reflective layer, which is formed prior to depositing a photoresist layer, improves an accuracy of a critical dimension (CD) of a pattern so that process latitude of the semiconductor device is increased.
Anti-reflective layers having the above-mentioned characteristics are generally classified as either inorganic anti-reflective layers or organic anti-reflective layers in accordance with compositions thereof. The inorganic anti-reflective layer exhibits favorable adhesion characteristics with respect to the stepped portion of the underlying layer. However, the inorganic anti-reflective layer is easily not removed in a subsequent process, and exhibits poor adhesion characteristics with respect to the photoresist pattern. Thus, the organic anti-reflective layer is widely utilized instead of the inorganic anti-reflective layer.
In a photolithography process using an organic anti-reflective layer, a composition of the organic anti-reflective layer is spin-coated on a layer to be etched. The composition is then baked to form the organic anti-reflective layer, and a photoresist film is formed on the organic anti-reflective layer. A soft baking process, an exposure process, a hard baking process, a developing process and a dry process are sequentially carried out on the photoresist film to form a photoresist pattern. The organic anti-reflective layer and the layer are sequentially etched using the photoresist pattern as an etching mask, thereby completing the photolithography process.
In this photolithography process, an important process parameter is an etched thickness of the photoresist pattern during the etching process for removing the organic anti-reflective layer from the layer.
Since the photoresist pattern is also etched during etching of the organic anti-reflective layer, a thickness of the photoresist pattern is substantially reduced. Thus, to provide the photoresist pattern with a desired etching selectivity, it is important to reduce the etched thickness of the photoresist pattern during etching of the organic anti-reflective layer.
However, the organic anti-reflective layer has an etch resistivity which is higher than that of a photoresist pattern for ArF or F2. Thus, the photoresist pattern may be excessively removed during etching of the organic anti-reflective layer. As a result, the excessively etched photoresist pattern may not sufficiently function as an etching mask in the etching process for removing the layer.
Therefore, in a case where the etching process for removing the organic anti-reflective layer is carried out, a new organic anti-reflective layer gets removed and prevents loss of the photoresist pattern.